ECU wont trigger fuel relay

[tomislav]

Hi

We have a Lotus with a K24 engine. The engine was swapped to another lotus and they put a new wire adaptor between the car and the engine.
We have hade a few issues because we didnt build the harness. The ecu was used in my other lotus but on this engine and it worked perfect.
Now when we are trying to start the new lotus the fuelpump wont start. We have 12v to the relay and can start the fuelpump manual. The startengine starts as it should but we dont get any fuel to the engine because the pump is not aktivated. We bypassed the imobiliser so that is not the issue.

We get 12v signal to the relay (we use lotus multi relay) but Hondata dont aktivates the pump (dont connect the signal to earth.

Other issues is that the car was built in 2008/2009 and the kpro is from that time. when i try to use the kpro i download on hondata i have issues with the comunication. it says its to old

Can i get a older version of the kpro or what should i do?

Kpro
Hardware version 2
Serial no 54xx
Firmware version 2.02
firmware ok: yes
Software 4.3.2.0
Ecu type PRB US RSX Type S

when we try to start the engine the crank turns and we get error "daughter communication error low voltage issue" But the pump needs to start before the startmotor

Thanks in advanced

Tomislav

[Spunkster]

What is the serial number that is on the K-Pro board inside the ECU?

[Hondata]

More than likely the fuel pump relay was wired so that the ECU grounded a 12V input, and the ECU output transistor is toast. The normal method of diagnosing this is to swap the ECU into a known good vehicle.
Check the wiring with the diagram here https://www.hondata.com/tech-k20-swap-wiring and make sure that the main, fuel and o2 relay wiring is correct.
I'm not sure if the Lotus relay module wiring is going to work, or if you have to run new relays. I removed mine and ran new relays as I did not trust the Lotus part.

[tomislav]

Hi

thanks for the superfast response.

The ecu serial number is 05005467
It looks like it fried.

I bought a lotus project car where malcolm in sweden was making the harness. There was some issues with the harness and we didnt get much support. Now we have found the issues on the harnes and the only thing not working was the fuelpump.

I put in a brand new k pro and the pump started. So now everything should be right.

So the issue remaining is

1. I have a file on my old k pro that i downloded but i cant upload it in a new version kpro, can it be converted?
2. when an ecu gets fried is it the honda part or the k pro part that needs to be replaced? What will it cost to fix it or should i buy a new one?
For now i can use the new k pro since my other lotus will be put together later this year

thanks for all you help

[Hondata]

1. The calibration file look fine. What happens when you try to upload.
2. At least the ECU fuel pump transistor, but if the fuel relay output was wired to +12V then the ECU ground rail can be raised higher than the internal +5V rail, which puts -7V across the ICs in the ECU and also the KPro, which can damage both the ECU and KPro.